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modern-qt/widget/image.impl.hh

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+#include "modern-qt/utility/painter/helper.hh"
+#include "image.hh"
+
+#include <qevent.h>
+#include <qpainter.h>
+#include <qpainterpath.h>
+#include <qpicture.h>
+#include <qwidget.h>
+
+using namespace creeper::image::internal;
+
+struct Image::Impl final {
+public:
+    explicit Impl(Image& self) noexcept
+        : self { self } { }
+
+    auto paint_event(const QPaintEvent&) noexcept {
+        const auto radius = get_radius();
+        const auto width  = self.width();
+        const auto height = self.height();
+
+        if (request_regenerate) regenerate_pixmap();
+
+        auto painter = QPainter { &self };
+        painter.setRenderHint(QPainter::Antialiasing);
+        painter.setRenderHint(QPainter::SmoothPixmapTransform);
+        painter.setOpacity(opacity);
+
+        if (resource_render && !resource_render->isNull()) {
+            const auto& pixmap = *resource_render;
+            const auto& point  = QPointF {
+                (width - pixmap.width()) / 2.,
+                (height - pixmap.height()) / 2.,
+            };
+            auto path = QPainterPath {};
+            path.addRoundedRect(border_width, border_width, width - 2 * border_width,
+                height - 2 * border_width, radius - border_width, radius - border_width);
+
+            painter.setBrush(Qt::NoBrush);
+            painter.setPen(Qt::NoPen);
+            painter.setClipPath(path);
+            painter.setClipping(true);
+            painter.drawPixmap(point, pixmap);
+        }
+        {
+            painter.setClipping(false);
+            util::PainterHelper { painter }.rounded_rectangle(
+                Qt::transparent, border_color, border_width, self.rect(), radius, radius);
+        }
+    }
+    auto resize_event(const QResizeEvent&) noexcept { request_regenerate = true; }
+
+private:
+    auto regenerate_pixmap() noexcept -> void {
+        if (!resource_origin) return;
+        if (resource_origin->isNull()) return;
+        const auto& _1     = *resource_origin;
+        const auto& _2     = self.size();
+        *resource_render   = content_scale.transform(_1, _2);
+        request_regenerate = false;
+    }
+
+    auto get_radius() const noexcept -> double {
+        return radius < 0 ? std::min<double>(self.width(), self.height()) / 2. : radius;
+    }
+
+public:
+    ContentScale content_scale;
+    bool request_regenerate = true;
+
+    double border_width = 02.;
+    QColor border_color = Qt::transparent;
+
+    double radius  = 10.;
+    double opacity = 01.;
+
+    std::shared_ptr<PainterResource> resource_origin {};
+    std::shared_ptr<PainterResource> resource_render {
+        std::make_shared<PainterResource>(QPixmap {}),
+    };
+
+    Image& self;
+};